Simple,
just simplify your problem....
[tex] 4a^{2} * -2a^{3} = -8a^{5}
(remember "multiplying" exponents adds them)[/tex]
[tex]b* b^{4} = b^{5} [/tex]
which just leaves you [tex] c^{2} [/tex] itself...now add them up....
Making your answer... [tex] -8a^{5} b^{5} c^{2} [/tex]
